A kind of high temperature resistant resin coated aramid paper and its manufacturing method and application

Abstract

The present invention relates to the technical field of insulating materials, and specifically to a high temperature resistant resin coated aramid paper and a manufacturing method and application thereof, wherein the high temperature resistant resin coated aramid paper is prepared by coating a mixed solution of meta-aramid polymer solution and a high temperature resistant resin solution on aramid paper, wherein the high temperature resistant resin solution comprises a matrix resin, a curing agent, a high thermal conductivity filler, a toughening agent, a promoter, an initiator, an active diluent and a solvent, wherein the glass transition temperature Tg of the matrix resin is ≥220°C or the long-term temperature resistance of the matrix resin is ≥200°C; the high thermal conductivity filler is fluorinated graphene or amino-modified fluorinated graphene; and the matrix resin contains at least the benzoxazine resin. The high temperature resistant resin coated aramid paper has high thermal conductivity and excellent mechanical strength, flame retardancy and insulation performance, which avoids the problem that the insulation performance of the aramid paper is greatly reduced and causes breakdown when the aramid paper is used in a harsh environment such as high air humidity.

Description

Technical Field

[0001] The invention relates to high temperature resistant resin coated aramid paper and a manufacturing method and application thereof, belonging to the technical field of insulating materials. Background Art

[0002] With the rapid development of power electronics technology and the gradual increase in the power of motors and transformers, new requirements are put forward for the mechanical strength, insulation performance, temperature resistance, moisture resistance and other properties of traditional insulating materials. Especially in high-frequency working environments, the heat generated by electrical equipment accumulates rapidly, and it is urgent to design and prepare paper-based insulating materials with high strength and high thermal conductivity, which can quickly and timely transfer the heat accumulated in the coils of electrical equipment to the heat dissipation equipment or insulating oil to ensure the normal operation of electrical equipment and extend its service life. Therefore, designing and developing insulating materials with high dielectric strength and high thermal conductivity has become the key to the miniaturization, lightweight and integration of electrical insulation equipment.

[0003] Aramid insulation paper has been widely used as an insulation and protection material in various medium and high voltage motors, reactors, transformers and other power equipment due to its outstanding mechanical strength, insulation properties and high temperature resistance, and has a very broad market prospect. Existing aramid insulation paper is made of meta-aramid fiber as the main raw material through wet papermaking and hot pressing processes. Since aramid paper has staggered distribution and no through-hole pores in its microstructure, although the dielectric properties are excellent under dry conditions, under special conditions such as high air humidity and salt water infiltration, the dielectric properties of aramid paper are greatly reduced, affecting its safety in use.

[0004] Chinese patent application CN113737569A discloses a method for preparing aramid paper by coating aramid paper with aramid spinning solution, and proposes to evenly coat the prepared meta-aramid spinning coating solution on both sides of the meta-aramid base paper to improve the dielectric strength of the aramid paper. Although the dielectric strength of the aramid paper is improved, the improvement effect is not significant.

[0005] A high dielectric composite aramid paper is disclosed in Chinese patent application CN112746522A, which proposes to combine the single-layer aramid paper including more than two layers into a whole through a high temperature resistant adhesive layer containing inorganic nano fillers to form a composite aramid paper, and the composite aramid paper obtained has better breakdown strength and corona resistance. However, due to the characteristics of the inertia of the aramid fiber surface and the weak interface bonding force of the two materials due to the interface effect, the bonding force between the high temperature resistant adhesive and the aramid paper is general, resulting in the limitation of various properties of the composite aramid paper as a whole (such as low dielectric strength). In addition, the resins or adhesives such as polyimide and epoxy resin used in the previous patents contain polar groups, which increases the water absorption or moisture regain of the aramid paper, and can cause the insulation performance in a high humidity environment to drop significantly.

[0006] In order to improve the bonding performance between resin and aramid paper and improve the dielectric properties of aramid paper under harsh conditions such as high humidity and salt spray, Chinese patent application CN109098043A discloses silicone resin coated aramid paper and its manufacturing method and application. After the aramid paper is acid-activated with dilute acid, a silane coupling agent is coated on the surface of the aramid paper as a binder, and then silicone resin is coated on the surface of the aramid paper containing the binder. The silicone resin coated aramid paper provided by the invention has good salt resistance, salt spray resistance, and waterproof penetration performance, and also has good weather resistance. However, the dilute acid and silane coupling agent treatment of aramid paper in the invention will reduce the mechanical properties of aramid paper to a certain extent. At the same time, the operation process of the invention is complicated, the control difficulty is relatively large, and it is difficult to achieve industrialization.

[0007] On the other hand, in order to improve the thermal conductivity of aramid paper, researchers usually use the following methods: adding high thermal conductivity fillers during the aramid paper making process or using high thermal conductivity fillers to modify precipitated fibers or adding high thermal conductivity fillers to aramid film and then hot pressing and compounding with aramid paper. The high thermal conductivity fillers usually used are boron nitride, aluminum nitride, etc. However, the thermal conductivity of these materials is not high, generally <50W / mK. Some patents also introduce graphene and other high thermal conductivity particles into aramid paper, but this also reduces the insulation of aramid paper. Summary of the invention

[0008] In view of the deficiencies in the prior art, the present invention provides a high-temperature resistant resin coated aramid paper and a manufacturing method and application thereof. The high-temperature resistant resin coated aramid paper has high thermal conductivity and excellent mechanical strength and insulation performance, and has a simple process and high efficiency. It avoids the problem that the dielectric properties of the aramid paper drop significantly when used in a harsh environment such as high air humidity, resulting in breakdown, and the like. At the same time, it can quickly and timely transfer the heat accumulated in the coil of the electrical equipment to the heat dissipation equipment or the insulating oil, thereby ensuring the normal operation of the electrical equipment and extending its service life.

[0009] The technical solution of the present invention to solve the above technical problems is as follows: a high temperature resistant resin coated aramid paper, the high temperature resistant resin coated aramid paper is prepared by coating a mixed solution of meta-aramid polymer solution and high temperature resistant resin solution on aramid paper, the high temperature resistant resin solution includes a matrix resin, a curing agent, a high thermal conductivity filler, a toughening agent, a promoter, an initiator, an active diluent and a solvent, the glass transition temperature Tg of the matrix resin is ≥220°C or the long-term temperature resistance of the matrix resin is ≥200°C; the high thermal conductivity filler is fluorinated graphene or amino-modified fluorinated graphene; the matrix resin contains at least the benzoxazine resin.

[0010] Furthermore, the matrix resin is one or a combination of benzoxazine resin, high heat-resistant epoxy resin, and polyarylate resin containing a phthalazinone structure;

[0011] The toughening agent is any one or a combination of hyperbranched epoxy resin, hyperbranched polyester, hyperbranched unsaturated resin and flexible benzoxazine.

[0012] Preferably, the mass percentage of the benzoxazine resin in the matrix resin is 60% to 100%, and the benzoxazine resin is a daidzein-furfurylamine type benzoxazine resin;

[0013] The fluorine content of the fluorinated graphene and the amino-modified fluorinated graphene is 35wt% to 60wt%, and the sheet diameter is 0.4 to 30μm.

[0014] Furthermore, the curing agent is one or a combination of aromatic amine curing agents and acid anhydride curing agents;

[0015] The accelerator is aluminum acetylacetonate or cobalt naphthenate;

[0016] The initiator is one or a combination of benzoyl peroxide and dicumyl peroxide;

[0017] The active diluent is one or a combination of 1,4-butanediol diacrylate or diallyl phthalate;

[0018] The solvent is one or a combination of N,N-dimethylformamide, N,N-dimethylacetamide, acetone, dichloromethane, chloroform, N-methylpyrrolidone, ethyl acetate and pyridine.

[0019] Furthermore, the mass ratio of the base resin, curing agent, high thermal conductive filler, toughening agent, accelerator, initiator and reactive diluent is (60-100): (2-5): (8-20): (10-30): (0.1-1): (0.1-1): (2-10);

[0020] The mass concentration of the meta-aramid polymer in the meta-aramid polymer solution is 10% to 35%; the mass concentration of the high temperature resistant resin in the high temperature resistant resin solution is 25% to 50%;

[0021] In the mixed solution obtained by uniformly mixing the meta-aramid polymer solution and the high temperature resistant resin solution, the mass proportion of the high temperature resistant resin solution is 5% to 50%.

[0022] Furthermore, the aramid paper is meta-aramid paper or para-aramid paper.

[0023] The present invention also discloses a preparation method of the high temperature resistant resin coated aramid paper, the preparation method comprising:

[0024] S1. Preparing aramid paper: mixing aramid short fibers, aramid fibrids and amino-modified fluorinated graphene, papermaking, pressing and drying, and subjecting the mixture to a hot press to obtain meta-aramid paper or para-aramid paper;

[0025] S2, preparing meta-aramid polymerization liquid;

[0026] S3, preparing a high temperature resistant resin solution: dissolving a base resin, a curing agent, a high thermal conductive filler, a toughening agent, an accelerator, an initiator and an active diluent in a solvent, and mixing them uniformly to obtain a high temperature resistant resin solution;

[0027] S4, preparing high temperature resistant resin coated aramid paper: the meta-aramid polymer solution prepared in step S2 and the high temperature resistant resin solution prepared in step S3 are mixed evenly to obtain a mixed solution, and then the mixed solution is evenly coated on both sides of the aramid paper, and then the solvent is dried and the resin is cured through a multi-stage drying process to obtain the high temperature resistant resin coated aramid paper.

[0028] Furthermore, in step S1, the aramid chopped fibers are one or both of meta-aramid chopped fibers and para-aramid chopped fibers; the aramid fibrids are meta-aramid fibrids, and the beating degree is 35-60° SR;

[0029] In terms of weight, the aramid short fibers are 35 to 70 parts, the aramid fibrids are 30 to 65 parts, and the amino-modified fluorinated graphene is 2 to 20 parts.

[0030] The hot pressing conditions in step S1 are: 220-350° C., pressure 15-35 MPa, roller speed 2-10 m / min, and hot pressing times 1-2 times.

[0031] Furthermore, in step S2, the preparation method of the meta-aramid polymer solution is: adding isophthaloyl chloride and meta-phenylenediamine to an organic solvent for polymerization reaction at -5 to 0°C and 14 to 15 kPa pressure in an inert gas dry environment, then adding a neutralizing agent, filtering and removing salt generated by the neutralization reaction, and obtaining the meta-aramid polymer solution;

[0032] The organic solvent is N, N-dimethylformamide or N, N-dimethylacetamide; the neutralizing agent is calcium oxide or calcium hydroxide.

[0033] In step S4, the multi-stage drying process is: first drying at 50-60°C for 20-90 minutes, then drying at 70-80°C for 20-90 minutes, then drying at 90-120°C for 20-120 minutes, then drying at 130-150°C for 1-2 hours, then drying at 170-190°C for 1-2 hours, and finally drying at 200-220°C for 1-2 hours.

[0034] The invention also discloses the application of the high temperature resistant resin coated aramid paper. The high temperature resistant resin coated aramid paper is used as heat conductive insulating paper in electrical insulation equipment of large motors, reactors and transformers.

[0035] The beneficial effects of the present invention are:

[0036] (1) Excellent aging and weather resistance

[0037] Polyarylate resin or fluorinated graphene has excellent UV shielding and weather resistance. Compared with traditional aramid paper, the insulating paper of the present invention has better UV resistance and weather resistance, which broadens the application field of aramid insulating paper. In particular, some new motors are designed to operate in ultraviolet environments, which can effectively avoid the problem of aramid paper aging and performance degradation caused by ultraviolet radiation to a certain extent.

[0038] (2) Excellent moisture resistance

[0039] In the high temperature resistant resin coated aramid paper of the present invention, the benzoxazine resin contained in the high temperature resistant resin forms a large number of hydrogen bonds after curing, and forms a "hydrogen bond complex" with the meta-aramid in the meta-aramid polymer solution, which significantly enhances the hydrophobicity and helps to shield the action of water molecules and polymers, so that it is difficult for water molecules to penetrate into the polymer, making it have low hygroscopicity, and improving the safety of aramid paper in special environments such as high humidity conditions. At the same time, the present invention also avoids the problem of poor moisture resistance caused by the introduction of conventional high temperature resistant resins (due to the presence of polar groups, poor moisture resistance).

[0040] (3) Excellent insulation

[0041] The benzoxazine resin contained in the high temperature resistant resin coating will solidify to produce many phenolic hydroxyl groups, forming a large number of hydrogen bonds. It will also produce hydrogen bonds with nitrogen or oxygen atoms in the meta-aramid to form a "hydrogen bond complex", which significantly improves the dielectric strength of the high temperature resistant resin coated aramid paper, thereby greatly improving the insulation performance of the insulating paper.

[0042] The benzoxazine resin, the meta-aramid polymer and the high thermal conductivity filler in the insulating paper of the present invention work together to make the insulating paper have excellent insulating properties and the advantages of being inherently flame retardant or high temperature resistant.

[0043] (4) Excellent thermal conductivity

[0044] The high temperature resistant resin coated aramid paper of the present invention has amino-modified fluorinated graphene or fluorinated graphene added to its high temperature resistant resin coating, which can effectively improve the thermal conductivity of the insulating paper and maintain good insulation performance. In addition, the amino-modified fluorinated graphene has good dispersibility in water, so that the processing of the aramid paper is smoother, which can avoid affecting the strength of the aramid paper and improve the thermal conductivity and insulation of the aramid paper. The high temperature resistant resin coated insulating paper finally obtained has high strength and excellent thermal conductivity and insulation.

[0045] (5) Stronger interface bonding strength

[0046] Compared with the method of coating a single non-aramid resin on aramid paper, the present invention uses a method of directly mixing meta-aramid polymer solution with a high temperature resistant resin solution and then coating it on the meta-aramid paper, thereby eliminating or reducing the influence of the weak interface bonding force caused by the interface effect between the two materials, and significantly improving the bonding between the meta-aramid paper and other resins. Compared with the prior art, the process of the present invention is simpler and more operable. More importantly, while achieving effective bonding between the high temperature resistant resin and the aramid paper, it avoids the negative effects of activation treatments such as dilute acid on the mechanical properties of the aramid paper. The present invention provides a universal, simple and efficient method for improving the bonding force between resin and aramid paper, which has important guiding significance for future scientific research or production. DETAILED DESCRIPTION

[0047] The specific implementation of the present invention is described in detail below. The present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used are only for describing specific embodiments and are not intended to limit the present invention.

[0049] A high temperature resistant resin coated aramid paper, the high temperature resistant resin coated aramid paper is prepared by coating a mixed solution of meta-aramid polymer solution and a high temperature resistant resin solution on aramid paper, the high temperature resistant resin solution comprises a matrix resin, a curing agent, a high thermal conductivity filler, a toughening agent, an accelerator, an initiator, an active diluent and a solvent, the matrix resin has a glass transition temperature Tg ≥ 220°C or the matrix resin has a long-term temperature resistance ≥ 200°C; the high thermal conductivity filler is fluorinated graphene or amino-modified fluorinated graphene; the matrix resin contains at least the benzoxazine resin.

[0050] Specifically, the matrix resin is one or a combination of benzoxazine resin, high heat-resistant epoxy resin, and polyarylate resin containing a phthalazinone structure;

[0051] The toughening agent is any one or a combination of hyperbranched epoxy resin, hyperbranched polyester, hyperbranched unsaturated resin and flexible benzoxazine.

[0052] Specifically, the mass percentage of the benzoxazine resin in the matrix resin is 60% to 100%, and the benzoxazine resin is a daidzein-furfurylamine type benzoxazine resin;

[0053] The fluorine content of the fluorinated graphene and the amino-modified fluorinated graphene is 35wt% to 60wt%, and the sheet diameter is 0.4 to 30μm.

[0054] The daidzein-furfurylamine type benzoxazine resin is homemade, and its preparation method is as follows: first, a certain amount of furfurylamine and polyformaldehyde are added to a toluene solvent, reacted at 50°C for 2 hours, and a uniform milky white mixture is obtained; then, a toluene solution containing daidzein is added to the mixture, reacted at 105°C for 8 to 10 hours, toluene solvent is removed by vacuum distillation at 70°C for 24 hours to obtain the daidzein-furfurylamine type benzoxazine resin. The molar ratio of furfurylamine, polyformaldehyde and daidzein required for the reaction is 2:4:1.

[0055] The high heat-resistant epoxy resin is selected from any one or a combination of XY-434L, XY-434, XY-433, ELM-100, and ELM-434.

[0056] XY-434L, XY-434, and XY-433 were purchased from Liaoyang Xinyu Chemical Co., Ltd., and ELM-100 and ELM-434 were purchased from Sumitomo Chemical.

[0057] The polyarylate resin containing diazolinone structure is self-made, and the specific preparation method is as follows: under nitrogen protection, 16mmol benzenesulfonyl chloride, 5ml pyridine, and 2.6mmol N,N-dimethylformamide are added in sequence to a 100ml three-necked flask equipped with a mechanical stirrer, and the mixture is reacted at room temperature for 30min. A pyridine solution of 5mmol 4-[4-(4-phenyloxy)phenyl]-2-(4-phenylphenyl)phthalazin-1-one is added to the reaction system, and the mixture is reacted at room temperature for 10min. The mixture is then heated to 120°C and reacted for 10min. A pyridine solution of 5mmol 4,4'-dihydroxydiphenylpropane is then added dropwise. After the addition is completed, the mixture is kept warm for reaction for 3h, and the reaction is stopped. The reaction solution is subjected to sedimentation, washing, and purification to obtain the polyarylate resin containing diazolinone structure. The reaction equation is:

[0058]

[0059] In the embodiment of the present invention, the hyperbranched epoxy resin is selected from any one or a combination of Hyper E101, Hyper E102, Hyper E103, Hyper E104, HyPer E201, HyPer E202, HyPer E203, HyPer E204, Hyper E301, 302, 303, 304, Hyper E401, Hyper402, Hyper403, and Hyper404 of Suzhou Haibote Resin Technology Co., Ltd.

[0060] The hyperbranched unsaturated resin is any one or a combination of HyPer U102, HUP-101, HUP-102, HUP-103, and HUP-104.

[0061] Among them, HyPer U102 was purchased from Wuhan Hyperbranched Resin Technology Co., Ltd.; HUP 10 series (HUP-101, HUP-102, HUP-103, HUP-104) were purchased from Suzhou Haibote Resin Technology Co., Ltd.

[0062] The flexible benzoxazine is homemade, the phenol for synthesizing the flexible benzoxazine can be any one of cardanol and nonylphenol, the amine can be any one of dodecylamine, tetradecylamine, hexadecylamine and octadecylamine, and the aldehyde is paraformaldehyde.

[0063] Taking nonylphenol, dodecylamine and polyformaldehyde as examples, the specific method for preparing nonylphenol-dodecylamine flexible benzoxazine resin is as follows: in a three-necked flask equipped with a condenser and stirred, nonylphenol and dodecylamine are stirred at 80°C for a period of time, then polyformaldehyde is added to react for a period of time and then heated to 110°C for 4 hours to obtain nonylphenol-dodecylamine flexible benzoxazine resin. The molar ratio of nonylphenol, dodecylamine and polyformaldehyde required for the reaction is 1:1:2. This method is also used to prepare other types of flexible benzoxazines, except that the corresponding phenolic substances and amine substances are replaced.

[0064] In the embodiment of the present invention, the fluorine content of fluorinated graphene (purchased from Xianfeng Nano, fluorine content: 53%-65%, sheet diameter: 4-10 μm) and amino-modified fluorinated graphene (self-made) are 35wt%-60wt% and 0.4-30 μm respectively.

[0065] The amino-modified fluorinated graphene in the embodiment of the present invention is homemade, and the specific preparation method is: grinding and mixing the fluorinated graphene and urea to obtain a mixture, the mass ratio of the fluorinated graphene to the urea is 1:500, and then adding the mixture to a reactor, under the protection of an inert gas, heating the mixture to 150°C for reaction for 4 hours, after cooling, adding distilled water to the reactor, filtering to obtain a black sample, and finally washing the black sample with distilled water and 95% ethanol three times respectively to obtain the amino-modified fluorinated graphene.

[0066] Specifically, the curing agent is one or a combination of aromatic amine curing agents and acid anhydride curing agents;

[0067] The accelerator is aluminum acetylacetonate or cobalt naphthenate;

[0068] The initiator is one or a combination of benzoyl peroxide and dicumyl peroxide;

[0069] The active diluent is one or a combination of 1,4-butanediol diacrylate or diallyl phthalate;

[0070] The solvent is one or a combination of N,N-dimethylformamide, N,N-dimethylacetamide, acetone, dichloromethane, chloroform, N-methylpyrrolidone, ethyl acetate and pyridine.

[0071] Specifically, the mass ratio of the base resin, curing agent, high thermal conductive filler, toughening agent, accelerator, initiator and active diluent is (60-100): (2-5): (8-20): (10-30): (0.1-1): (0.1-1): (2-10);

[0072] The mass concentration of the meta-aramid polymer in the meta-aramid polymer solution is 10% to 35%; the mass concentration of the high temperature resistant resin in the high temperature resistant resin solution is 25% to 50%;

[0073] In the mixed solution obtained by uniformly mixing the meta-aramid polymer solution and the high temperature resistant resin solution, the mass proportion of the high temperature resistant resin solution is 5% to 50%.

[0074] Specifically, the aramid paper is meta-aramid paper or para-aramid paper.

[0075] The present invention also discloses a preparation method of the high temperature resistant resin coated aramid paper, the preparation method comprising:

[0076] S1. Preparing aramid paper: mixing aramid short fibers, aramid fibrids and amino-modified fluorinated graphene, papermaking, pressing and drying, and subjecting the mixture to a hot press to obtain meta-aramid paper or para-aramid paper;

[0077] S2, preparing meta-aramid polymerization liquid;

[0078] S3, preparing a high temperature resistant resin solution: dissolving a base resin, a curing agent, a high thermal conductive filler, a toughening agent, an accelerator, an initiator and an active diluent in a solvent, and mixing them uniformly to obtain a high temperature resistant resin solution;

[0079] S4, preparing high temperature resistant resin coated aramid paper: the meta-aramid polymer solution prepared in step S2 and the high temperature resistant resin solution prepared in step S3 are mixed evenly to obtain a mixed solution, and then the mixed solution is evenly coated on both sides of the aramid paper, and then the solvent is dried and the resin is cured through a multi-stage drying process to obtain the high temperature resistant resin coated aramid paper.

[0080] Specifically, in step S1, the aramid chopped fibers are one or both of meta-aramid chopped fibers and para-aramid chopped fibers; the aramid fibrids are meta-aramid fibrids, and the beating degree is 35-60°SR;

[0081] In terms of weight, the aramid short fibers are 35 to 70 parts, the aramid fibrids are 30 to 65 parts, and the amino-modified fluorinated graphene is 2 to 20 parts.

[0082] The hot pressing conditions in step S1 are: 220-350° C., pressure 15-35 MPa, roller speed 2-10 m / min, and hot pressing times 1-2 times.

[0083] Specifically, in step S2, the preparation method of the meta-aramid polymer solution is: adding isophthaloyl chloride and meta-phenylenediamine to an organic solvent for polymerization reaction under an inert gas dry environment at -5 to 0°C and a pressure of 14 to 15 kPa, then adding a neutralizing agent, filtering and removing salt generated by the neutralization reaction, and obtaining the meta-aramid polymer solution;

[0084] The organic solvent is N, N-dimethylformamide or N, N-dimethylacetamide; the neutralizing agent is calcium oxide or calcium hydroxide.

[0085] In step S4, the multi-stage drying process is: first drying at 50-60°C for 20-90 minutes, then drying at 70-80°C for 20-90 minutes, then drying at 90-120°C for 20-120 minutes, then drying at 130-150°C for 1-2 hours, then drying at 170-190°C for 1-2 hours, and finally drying at 200-220°C for 1-2 hours.

[0086] Example 1

[0087] Step 1: Preparation of meta-aramid paper

[0088] Take 39 parts of meta-aramid fiber precipitate (beating degree is 35°SR), 61 parts of meta-aramid short fibers, and 12 parts of amino fluorinated graphene, pulp them separately, then mix, paper, press, and dry to obtain meta-aramid base paper, and then pass through a roller hot press to perform high temperature and high pressure hot pressing to obtain meta-aramid paper. Hot pressing treatment conditions: temperature 220°C, pressure 15MPa, roller speed 4m / min. The thickness of the obtained meta-aramid paper is 0.05mm.

[0089] Step 2: Preparation of meta-aramid polymer solution

[0090] In a 15 kPa pressure nitrogen dry environment, at -5 to 0° C., isophthaloyl chloride and meta-phenylenediamine are added to N,N-dimethylacetamide for polymerization reaction, and then calcium oxide is added to neutralize the hydrogen chloride dissolved in the polymerization solution, and the salt generated by the neutralization reaction is filtered out to obtain a meta-aramid polymerization solution with a polymer mass concentration of 10%.

[0091] Step 3: Preparation of high temperature resistant resin solution

[0092] The specific raw material composition is as shown in Table 1:

[0093] Table 1 Raw materials of high temperature resistant resin solution of Example 1

[0094]

[0095] The base resin, curing agent, high thermal conductive filler, toughening agent, accelerator, initiator and active diluent are dissolved in a solvent and mixed evenly to prepare a high temperature resistant resin solution, the mass percentage of which is 25%.

[0096] Step 4: Preparation of high temperature resistant resin coated aramid paper

[0097] The meta-aramid polymer solution prepared in step 2 and the high temperature resistant resin solution prepared in step 3 are mixed evenly to obtain a mixed solution, in which the mass proportion of the high temperature resistant resin solution in the mixed solution is 30%, and then the mixed solution is evenly coated on both sides of the meta-aramid paper in step 1, and then the solvent is dried and the resin is solidified through a multi-stage drying process to obtain the high temperature resistant resin coated aramid paper. The multi-stage drying process is: first drying at 50°C for 20 minutes, then drying at 70°C for 30 minutes, then drying at 90°C for 30 minutes, then drying at 110°C for 60 minutes, then drying at 130°C for 60 minutes, then drying at 170°C for 2 hours, and finally drying at 210°C for 2 hours.

[0098] The thickness of the high temperature resistant resin coated aramid paper in this embodiment is 0.08 mm, and the performance indicators are detailed in Table 8.

[0099] Example 2

[0100] Step 1: Preparation of meta-aramid paper

[0101] Take 42 parts of meta-aramid fiber precipitation (beating degree is 60°SR), 58 parts of meta-aramid short fibers, and 8 parts of amino fluorinated graphene, pulp them separately, then mix, paper, press, and dry to obtain meta-aramid base paper, and then pass through a roller hot press to obtain meta-aramid paper under high temperature and high pressure hot pressing. High temperature and high pressure hot pressing conditions: temperature 250℃, pressure 18MPa, roller speed 5m / min. The thickness of the obtained meta-aramid paper is 0.08mm.

[0102] Step 2: Preparation of meta-aramid polymer solution

[0103] In a 14 kPa pressure nitrogen dry environment, at -5 to 0°C, isophthaloyl chloride and meta-phenylenediamine are added to N,N-dimethylformamide for polymerization reaction, and then calcium hydroxide is added to neutralize the hydrogen chloride dissolved in the polymerization solution, and the salt generated by the neutralization reaction is filtered out to obtain a meta-aramid polymerization solution with a polymer mass concentration of 20%.

[0104] Step 3: Preparation of high temperature resistant resin solution

[0105] The specific raw material composition is as shown in Table 2:

[0106] Table 2 Raw materials of high temperature resistant resin solution of Example 2

[0107]

[0108] The base resin, curing agent, high thermal conductive filler, toughening agent, accelerator, initiator and active diluent are dissolved in a solvent and mixed evenly to prepare a high temperature resistant resin solution, the mass percentage of which is 40%.

[0109] Step 4: Preparation of high temperature resistant resin coated aramid paper

[0110] The meta-aramid polymer solution prepared in step 2 and the high temperature resistant resin solution prepared in step 3 are mixed evenly to obtain a mixed solution, in which the mass proportion of the high temperature resistant resin solution in the mixed solution is 50%, and then the mixed solution is evenly coated on both sides of the meta-aramid paper in step 1, and then the solvent is dried and the resin is solidified through a multi-stage drying process to obtain the high temperature resistant resin coated aramid paper. The multi-stage drying process is: first drying at 55°C for 30 minutes, then drying at 75°C for 30 minutes, then drying at 95°C for 30 minutes, then drying at 115°C for 60 minutes, then drying at 145°C for 2 hours, then drying at 180°C for 2 hours, and finally drying at 210°C for 2 hours.

[0111] The thickness of the high temperature resistant resin coated aramid paper in this embodiment is 0.12 mm, and the performance indicators are detailed in Table 8.

[0112] Example 3

[0113] Step 1: Preparation of meta-aramid paper

[0114] Take 35 parts of meta-aramid fiber precipitation (beating degree is 49°SR), 65 parts of meta-aramid short fibers, and 14 parts of amino fluorinated graphene, pulp them separately, then mix, paper, press, and dry to obtain meta-aramid base paper, and then pass through a roller hot press to obtain meta-aramid paper under high temperature and high pressure hot pressing. High temperature and high pressure hot pressing conditions: temperature 290℃, pressure 15MPa, roller speed 10m / min. The thickness of the obtained meta-aramid paper is 0.13mm.

[0115] Step 2: Preparation of meta-aramid polymer solution

[0116] In a 15 kPa pressure nitrogen dry environment, at -5 to 0° C., isophthaloyl chloride and meta-phenylenediamine are added to N,N-dimethylacetamide for polymerization reaction, and then calcium hydroxide is added to neutralize the hydrogen chloride dissolved in the polymerization solution, and the salt generated by the neutralization reaction is filtered out to obtain a meta-aramid polymerization solution with a polymer mass concentration of 25%.

[0117] Step 3: Preparation of high temperature resistant resin solution

[0118] The specific raw material composition is as shown in Table 3:

[0119] Table 3 Raw materials of high temperature resistant resin solution of Example 3

[0120]

[0121]

[0122] The base resin, curing agent, high thermal conductive filler, toughening agent, accelerator, initiator and active diluent are dissolved in a solvent and mixed evenly to prepare a high temperature resistant resin solution, the mass percentage of which is 50%.

[0123] Step 4: Preparation of high temperature resistant resin coated aramid paper

[0124] The meta-aramid polymer solution prepared in step 2 and the high temperature resistant resin solution prepared in step 3 are mixed evenly to obtain a mixed solution, in which the mass proportion of the high temperature resistant resin solution in the mixed solution is 5%, and then the mixed solution is evenly coated on both sides of the meta-aramid paper in step 1, and then the solvent is dried and the resin is solidified through a multi-stage drying process to obtain the high temperature resistant resin coated aramid paper. The multi-stage drying process is: first drying at 50°C for 30 minutes, then drying at 70°C for 20 minutes, then drying at 90°C for 30 minutes, then drying at 110°C for 60 minutes, then drying at 140°C for 2 hours, then drying at 170°C for 2 hours, and finally drying at 210°C for 2 hours.

[0125] The thickness of the high temperature resistant resin coated aramid paper in this embodiment is 0.16 mm, and the performance indicators are detailed in Table 8.

[0126] Example 4

[0127] Step 1: Preparation of meta-aramid paper

[0128] Take 70 parts of meta-aramid fiber precipitation (beating degree is 40°SR), 30 parts of meta-aramid short fibers, and 2 parts of amino fluorinated graphene, pulp them separately, then mix, paper, press, and dry to obtain meta-aramid base paper, and then pass through a roller hot press to perform high temperature and high pressure hot pressing to obtain meta-aramid paper. Hot pressing treatment conditions: temperature 350°C, pressure 30MPa, roller speed 2m / min. The thickness of the obtained meta-aramid paper is 0.05mm.

[0129] Step 2: Preparation of meta-aramid polymer solution

[0130] In a 15 kPa pressure nitrogen dry environment, at -5 to 0° C., isophthaloyl chloride and meta-phenylenediamine are added to N,N-dimethylacetamide for polymerization reaction, and then calcium hydroxide is added to neutralize the hydrogen chloride dissolved in the polymerization solution, and the salt generated by the neutralization reaction is filtered out to obtain a meta-aramid polymerization solution with a polymer mass concentration of 35%.

[0131] Step 3: Preparation of high temperature resistant resin solution

[0132] The specific raw material composition is shown in Table 4:

[0133] Table 4 Raw materials of high temperature resistant resin solution of Example 4

[0134]

[0135]

[0136] The base resin, curing agent, high thermal conductive filler, toughening agent, accelerator, initiator and active diluent are dissolved in a solvent and mixed evenly to prepare a high temperature resistant resin solution, the mass percentage of which is 50%.

[0137] Step 4: Preparation of high temperature resistant resin coated aramid paper

[0138] The meta-aramid polymer solution prepared in step 2 and the high temperature resistant resin solution prepared in step 3 are mixed evenly to obtain a mixed solution, in which the mass proportion of the high temperature resistant resin solution in the mixed solution is 15%, and then the mixed solution is evenly coated on both sides of the meta-aramid paper in step 1, and then the solvent is dried and the resin is solidified through a multi-stage drying process to obtain the high temperature resistant resin coated aramid paper. The multi-stage drying process is: first drying at 60°C for 90 minutes, then drying at 80°C for 90 minutes, then drying at 100°C for 20 minutes, then drying at 120°C for 20 minutes, then drying at 150°C for 60 minutes, then drying at 180°C for 1 hour, and finally drying at 200°C for 1 hour.

[0139] The thickness of the high temperature resistant resin coated aramid paper in this embodiment is 0.08 mm, and the performance indicators are detailed in Table 8.

[0140] Example 5

[0141] Step 1: Preparation of meta-aramid paper

[0142] Take 40 parts of meta-aramid fiber precipitation (beating degree is 50°SR), 60 parts of meta-aramid short fibers, and 20 parts of amino fluorinated graphene, pulp them separately, then mix, paper, press, and dry to obtain meta-aramid base paper, and then pass through a roller hot press to perform high temperature and high pressure hot pressing to obtain meta-aramid paper. High temperature and high pressure hot pressing conditions: temperature 350℃, pressure 18MPa, roller speed 5m / min. The thickness of the obtained meta-aramid paper is 0.08mm.

[0143] Step 2: Preparation of meta-aramid polymer solution

[0144] In a 14 kPa pressure nitrogen dry environment, at -5 to 0° C., isophthaloyl chloride and meta-phenylenediamine are added to N,N-dimethylacetamide for polymerization reaction, and then calcium oxide is added to neutralize the hydrogen chloride dissolved in the polymerization solution, and the salt generated by the neutralization reaction is filtered out to obtain a meta-aramid polymerization solution with a polymer mass concentration of 30%.

[0145] Step 3: Preparation of high temperature resistant resin solution

[0146] The specific raw material composition is as shown in Table 5:

[0147] Table 5 Raw materials of high temperature resistant resin solution of Example 5

[0148]

[0149] The base resin, curing agent, high thermal conductive filler, toughening agent, accelerator, initiator and active diluent are dissolved in a solvent and mixed evenly to prepare a high temperature resistant resin solution, the mass percentage of which is 45%.

[0150] Step 4: Preparation of high temperature resistant resin coated aramid paper

[0151] The meta-aramid polymer solution prepared in step 2 and the high temperature resistant resin solution prepared in step 3 are mixed evenly to obtain a mixed solution, in which the mass proportion of the high temperature resistant resin solution in the mixed solution is 10%, and then the mixed solution is evenly coated on both sides of the meta-aramid paper in step 1, and then the solvent is dried and the resin is solidified through a multi-stage drying process to obtain the high temperature resistant resin coated aramid paper. The multi-stage drying process is: first drying at 55°C for 30 minutes, then drying at 75°C for 60 minutes, then drying at 90°C for 120 minutes, then drying at 110°C for 120 minutes, then drying at 130°C for 1 hour, then drying at 190°C for 2 hours, and finally drying at 220°C for 1 hour.

[0152] The thickness of the high temperature resistant resin coated aramid paper in this embodiment is 0.12 mm, and the performance indicators are detailed in Table 8.

[0153] Example 6

[0154] Step 1: Preparation of para-aramid paper

[0155] Take 39 parts of meta-aramid fiber precipitation (beating degree is 48°SR), 61 parts of para-aramid short fibers, and 10 parts of amino fluorinated graphene, pulp them separately, then mix, paper, press, and dry to obtain para-aramid base paper, and then pass through a roller hot press to obtain para-aramid paper under high temperature and high pressure hot pressing. High temperature and high pressure hot pressing conditions: temperature 250℃, pressure 18MPa, roller speed 5m / min. The thickness of the obtained para-aramid paper is 0.08mm.

[0156] Step 2: Preparation of meta-aramid polymer solution

[0157] In a 15 kPa pressure nitrogen dry environment, at -5 to 0° C., isophthaloyl chloride and meta-phenylenediamine are added to N,N-dimethylacetamide for polymerization reaction, and then calcium oxide is added to neutralize the hydrogen chloride dissolved in the polymerization solution, and the salt generated by the neutralization reaction is filtered out to obtain a meta-aramid polymerization solution with a polymer mass concentration of 20%.

[0158] Step 3: Preparation of high temperature resistant resin solution

[0159] The specific raw material composition is shown in Table 6:

[0160] Table 6 Raw materials of high temperature resistant resin solution of Example 6

[0161]

[0162] The base resin, curing agent, high thermal conductive filler, toughening agent, accelerator, initiator and active diluent are dissolved in a solvent and mixed evenly to prepare a high temperature resistant resin solution, the mass percentage of which is 40%.

[0163] Step 4: Preparation of high temperature resistant resin coated aramid paper

[0164] The meta-aramid polymer solution prepared in step 2 and the high temperature resistant resin solution prepared in step 3 are mixed evenly to obtain a mixed solution, in which the mass proportion of the high temperature resistant resin solution in the mixed solution is 30%, and then the mixed solution is evenly coated on both sides of the para-aramid paper in step 1, and then the solvent is dried and the resin is solidified through a multi-stage drying process to obtain the high temperature resistant resin coated aramid paper. The multi-stage drying process is: first drying at 50°C for 20 minutes, then drying at 70°C for 30 minutes, then drying at 90°C for 30 minutes, then drying at 110°C for 60 minutes, then drying at 130°C for 60 minutes, then drying at 170°C for 2 hours, and finally drying at 210°C for 2 hours.

[0165] The thickness of the high temperature resistant resin coated aramid paper in this embodiment is 0.12 mm, and the performance indicators are detailed in Table 8.

[0166] Example 7

[0167] Step 1: Preparation of para-aramid paper

[0168] Take 30 parts of meta-aramid fiber precipitation (beating degree is 46°SR), 70 parts of para-aramid short fibers, and 15 parts of amino fluorinated graphene, pulp them separately, then mix, paper, press, and dry to obtain meta-aramid base paper, and then pass through a roller hot press to obtain para-aramid paper under high temperature and high pressure hot pressing. High temperature and high pressure hot pressing conditions: temperature 280℃, pressure 15MPa, roller speed 8m / min. The thickness of the obtained para-aramid paper is 0.05mm.

[0169] Step 2: Preparation of meta-aramid polymer solution

[0170] In a 14 kPa pressure nitrogen dry environment, at -5 to 0°C, isophthaloyl chloride and meta-phenylenediamine are added to N,N-dimethylformamide for polymerization reaction, and then calcium hydroxide is added to neutralize the hydrogen chloride dissolved in the polymerization solution, and the salt generated by the neutralization reaction is filtered out to obtain a meta-aramid polymerization solution with a polymer mass concentration of 20%.

[0171] Step 3: Preparation of high temperature resistant resin solution

[0172] The specific raw material composition is shown in Table 7:

[0173] Table 7 Raw materials of high temperature resistant resin solution of Example 7

[0174]

[0175] The base resin, curing agent, high thermal conductive filler, toughening agent, accelerator, initiator and active diluent are dissolved in a solvent and mixed evenly to prepare a high temperature resistant resin solution, the mass percentage of which is 35%.

[0176] Step 4: Preparation of high temperature resistant resin coated aramid paper

[0177] The meta-aramid polymer solution prepared in step 2 and the high temperature resistant resin solution prepared in step 3 are mixed evenly to obtain a mixed solution, in which the mass proportion of the high temperature resistant resin solution in the mixed solution is 45%, and then the mixed solution is evenly coated on both sides of the meta-aramid paper in step 1, and then the solvent is dried and the resin is solidified through a multi-stage drying process to obtain the high temperature resistant resin coated aramid paper. The multi-stage drying process is: first drying at 55°C for 30 minutes, then drying at 75°C for 30 minutes, then drying at 95°C for 30 minutes, then drying at 115°C for 60 minutes, then drying at 145°C for 2 hours, then drying at 180°C for 1 hour, and finally drying at 210°C for 2 hours.

[0178] The thickness of the high temperature resistant resin coated aramid paper in this embodiment is 0.08 mm, and the performance indicators are detailed in Table 8.

[0179] Comparative Example 1

[0180] According to the same method as step 1 of Example 1, meta-aramid paper with a thickness of 0.08 mm was prepared, and the corresponding properties of the prepared meta-aramid paper were tested, see Table 8.

[0181] Comparative Example 2

[0182] The high temperature resistant resin coated aramid paper was prepared in the same manner as in Example 1, except that the meta-aramid polymer solution was not added, and the high temperature resistant resin solution was directly coated on both sides of the meta-aramid paper. The thickness of the high temperature resistant resin coated aramid paper finally obtained was 0.08 mm, and the corresponding performance tests were shown in Table 8.

[0183] Comparative Example 3

[0184] The high temperature resistant resin coated aramid paper was prepared in the same manner as in Example 1, except that the high temperature resistant resin solution was not added, and the meta-aramid polymer solution was directly coated on both sides of the meta-aramid paper. The thickness of the high temperature resistant resin coated aramid paper finally obtained was 0.08 mm, and the corresponding performance tests were shown in Table 8.

[0185] Comparative Example 4

[0186] The high temperature resistant resin coated aramid paper was prepared in the same manner as in Example 1, except that, in step 3: during the preparation of the high temperature resistant resin solution, the base resin did not contain daidzein-furfurylamine type benzoxazine resin, and the base resin was 85 parts of a polyarylate resin containing a phthalazinone structure. The thickness of the high temperature resistant resin coated aramid paper finally obtained was 0.08 mm, and the corresponding performance tests were shown in Table 8.

[0187] Comparative Example 5

[0188] Insulating paper was prepared in the same manner as in Example 1, except that no fluorinated graphene was added to the high temperature resistant resin solution. The properties of the obtained high temperature resistant resin coated aramid paper are shown in Table 8.

[0189] Comparative Example 6

[0190] Insulating paper was prepared in the same manner as in Example 1, except that amino-modified fluorinated graphene was not added in the preparation of the meta-aramid paper. The properties of the obtained high temperature resistant resin coated aramid paper are shown in Table 8.

[0191] Comparative Example 7

[0192] Insulating paper was prepared in the same manner as in Example 1, except that when preparing the high temperature resistant resin solution, the fluorinated graphene was replaced with boron nitride. The properties of the obtained high temperature resistant resin coated aramid paper are shown in Table 8.

[0193] Comparative Example 8

[0194] Insulating paper was prepared in the same manner as in Example 1, except that when preparing the high temperature resistant resin solution, fluorinated graphene was replaced with graphene. The properties of the obtained high temperature resistant resin coated aramid paper are shown in Table 8.

[0195] Table 8 Performance data of high temperature resistant resin coated aramid paper

[0196]

[0197] Note: When the thickness is ≤0.13mm, the tearing strength refers to the internal tearing strength; when the thickness is greater than 0.13mm, the tearing strength refers to the edge tearing strength.

[0198] It can be seen from the data in Table 8 that the high temperature resistant resin coated aramid paper prepared by the method of the present invention in Examples 1 to 7 has high mechanical properties, high dielectric strength and good thermal conductivity. However, the thermal conductivity and dielectric strength of the meta-aramid paper prepared in Comparative Example 1 are significantly reduced. The dielectric strength of the high temperature resistant resin coated aramid paper prepared in Example 1 is increased by 254% compared with Comparative Example 1, and the tensile strength of the high temperature resistant resin coated aramid paper prepared in Example 1 is also significantly higher than that of Comparative Example 1.

[0199] From the data comparison between comparative example 2 and example 1, it can be seen that if the meta-aramid polymer solution is not added during the preparation of the high temperature resistant resin coated aramid paper, the dielectric strength of the prepared high temperature resistant resin coated aramid paper is significantly reduced. From the data comparison between comparative example 3 and example 1, it can be seen that if the high temperature resistant resin solution is not added, the dielectric strength of the prepared high temperature resistant resin coated aramid paper is significantly reduced. From the comparison between the experimental data of comparative examples 2-3 and example 1, it can be clearly seen that only by applying the high temperature resistant resin solution and the meta-aramid polymer together in the high temperature resistant resin coated aramid paper can the high temperature resistant resin coated aramid paper have excellent insulation properties. The benzoxazine resin contained in the high temperature resistant resin coating is cured to produce many phenolic hydroxyl groups, forming a large number of hydrogen bonds, and at the same time, it will also produce hydrogen bonds with nitrogen or oxygen atoms in the meta-aramid to form a "hydrogen bond complex", producing a synergistic effect, so that the dielectric strength of the high temperature resistant resin coated aramid paper is significantly improved.

[0200] From the data comparison of comparative examples 5 and 6 with example 1, it can be seen that the addition of fluorinated graphene and amino-modified fluorinated graphene can effectively improve the thermal conductivity of the high temperature resistant resin coated aramid paper while ensuring that the high temperature resistant resin coated aramid paper has good insulation and mechanical properties. The fluorinated graphene can be well integrated with the matrix resin in the high temperature resistant resin solution and play a synergistic role, so that the high temperature resistant resin coated aramid paper has good insulation, thermal conductivity and mechanical properties.

[0201] It can be seen from the data of Comparative Example 7 that if the fluorinated graphene is replaced with conventional boron nitride, the thermal conductivity of the high temperature resistant resin coated aramid paper decreases, which indicates that the thermal conductivity of the fluorinated graphene is significantly better than that of boron nitride.

[0202] It can be seen from the data of Comparative Example 8 that: based on the certain conductivity of graphene, if the fluorinated graphene is replaced with graphene, the dielectric strength of the high temperature resistant resin coated aramid paper will be significantly reduced, and it cannot meet the fields with higher insulation requirements.

[0203] The high temperature resistant resin coated aramid paper of the present invention has good moisture-proof performance in addition to having good mechanical properties, insulation properties and thermal conductivity. To verify the moisture-proof performance, the high temperature resistant resin coated aramid paper of Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 were placed in an environment with a humidity of 70% to 80% and a temperature of 40°C for 180 days, and the dielectric strength data were measured again. The specific results are shown in Table 9 below.

[0204] Table 9 Moisture-proof performance evaluation

[0205]

[0206]

[0207] Note: Humidity is 70% to 80%, temperature is 40℃.

[0208] From the data in Table 9, it can be seen that the high temperature resistant resin coated aramid paper prepared by the method of the present invention in Example 1 still has a high dielectric strength after being placed in a humid environment, meets the requirements of insulation performance, and can be applied to various high humidity environments. However, Comparative Examples 1, 2, 3, and 4 did not use the method of the present invention to prepare the high temperature resistant resin coated aramid paper. The main difference from the present invention is that the meta-aramid polymer solution, high temperature resistant resin solution, or benzoxazine resin described in the present invention was not used. The obtained high temperature resistant resin coated aramid paper is easy to absorb moisture after being placed in a high humidity environment, which ultimately affects the insulation performance of the high temperature resistant resin coated aramid paper.

[0209] The benzoxazine resin contained in Example 1 forms a large number of hydrogen bonds after curing to form a "hydrogen bond complex" with the meta-aramid, which reduces the hygroscopicity of the pure aramid coating or the pure resin coating, and improves the application performance of the high temperature resistant resin coated aramid paper in special environments, such as the insulation performance under high humidity conditions. In the preparation process of the high temperature resistant resin coated aramid paper of the present invention, the high temperature resistant resin and the meta-aramid polymer produce a synergistic effect, effectively improving the moisture resistance of the high temperature resistant resin coated aramid paper.

[0210] In summary, the high temperature resistant resin coated aramid paper of the present invention can provide higher dielectric protection performance for large motors, reactors, transformers and other equipment, thereby extending the service life of the motor, reducing maintenance costs and improving production efficiency.

[0211] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are exhaustively listed. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0212] For those skilled in the art, several modifications and improvements may be made without departing from the concept of the present invention, all of which belong to the protection scope of the present invention. The protection scope of the present invention shall be based on the attached claims.

Claims

1. A high temperature resistant resin coated aramid paper, characterized in that: The high temperature resistant resin coated aramid paper is prepared by coating a mixed solution of meta-aramid polymer solution and high temperature resistant resin solution on aramid paper, wherein the high temperature resistant resin solution comprises a base resin, a curing agent, a high thermal conductivity filler, a toughening agent, an accelerator, an initiator, an active diluent and a solvent, wherein the base resin has a glass transition temperature Tg ≥ 220°C or a long-term temperature resistance of the base resin ≥ 200°C; the high thermal conductivity filler is amino-modified fluorinated graphene; and the base resin contains at least benzoxazine resin; The mass percentage of the benzoxazine resin in the matrix resin is 60% to 100%, and the benzoxazine resin is a daidzein-furfurylamine type benzoxazine resin; The fluorine content of the amino-modified fluorinated graphene is 35wt%-60wt%, and the sheet diameter is 0.4-30μm.

2. The high temperature resistant resin coated aramid paper according to claim 1, characterized in that: The matrix resin is one or a combination of benzoxazine resin, high heat-resistant epoxy resin, and polyarylate resin containing a phthalazinone structure; The toughening agent is any one or a combination of hyperbranched epoxy resin, hyperbranched polyester, hyperbranched unsaturated resin and flexible benzoxazine.

3. The high temperature resistant resin coated aramid paper according to claim 1, characterized in that: The curing agent is one or a combination of aromatic amine curing agents and acid anhydride curing agents; The accelerator is aluminum acetylacetonate or cobalt naphthenate; The initiator is one or a combination of benzoyl peroxide and dicumyl peroxide; The active diluent is one or a combination of 1,4-butanediol diacrylate or diallyl phthalate; The solvent is one or a combination of N,N-dimethylformamide, N,N-dimethylacetamide, acetone, dichloromethane, chloroform, N-methylpyrrolidone, ethyl acetate and pyridine.

4. The high temperature resistant resin coated aramid paper according to claim 1, characterized in that: The mass ratio of the base resin, curing agent, high thermal conductive filler, toughening agent, accelerator, initiator and active diluent is (60-100): (2-5): (8-20): (10-30): (0.1-1): (0.1-1): (2-10); The mass concentration of the meta-aramid polymer in the meta-aramid polymer solution is 10% to 35%; the mass concentration of the high temperature resistant resin in the high temperature resistant resin solution is 25% to 50%; In the mixed solution obtained by uniformly mixing the meta-aramid polymer solution and the high temperature resistant resin solution, the mass proportion of the high temperature resistant resin solution is 5% to 50%.

5. The high temperature resistant resin coated aramid paper according to claim 1, characterized in that: The aramid paper is meta-aramid paper or para-aramid paper.

6. A method for preparing a high temperature resistant resin coated aramid paper according to any one of claims 1 to 5, characterized in that: The preparation method is: S1. Preparing aramid paper: mixing aramid short fibers, aramid fibrids and amino-modified fluorinated graphene, papermaking, pressing and drying, and subjecting the mixture to a hot press to obtain meta-aramid paper or para-aramid paper; S2, preparing meta-aramid polymerization liquid; S3, preparing a high temperature resistant resin solution: dissolving a base resin, a curing agent, a high thermal conductive filler, a toughening agent, an accelerator, an initiator and an active diluent in a solvent, and mixing them uniformly to obtain a high temperature resistant resin solution; S4, preparing high temperature resistant resin coated aramid paper: the meta-aramid polymer solution prepared in step S2 and the high temperature resistant resin solution prepared in step S3 are mixed evenly to obtain a mixed solution, and then the mixed solution is evenly coated on both sides of the aramid paper, and then the solvent is dried and the resin is cured through a multi-stage drying process to obtain the high temperature resistant resin coated aramid paper.

7. The method for preparing a high temperature resistant resin coated aramid paper according to claim 6, characterized in that: In step S1, the aramid chopped fibers are one or both of meta-aramid chopped fibers and para-aramid chopped fibers; the aramid fibrids are meta-aramid fibrids, and the beating degree is 35-60°SR; In terms of weight, the aramid short fibers are 35 to 70 parts, the aramid fibrils are 30 to 65 parts, and the amino-modified fluorinated graphene is 2 to 20 parts.

8. The method for preparing a high temperature resistant resin coated aramid paper according to claim 6, characterized in that: In step S2, the preparation method of the meta-aramid polymer solution is as follows: adding isophthaloyl chloride and meta-phenylenediamine to an organic solvent for polymerization reaction under an inert gas dry environment at -5 to 0°C and a pressure of 14 to 15 kPa, then adding a neutralizing agent, filtering and removing salt generated by the neutralization reaction, and obtaining the meta-aramid polymer solution; The organic solvent is N, N-dimethylformamide or N, N-dimethylacetamide; the neutralizing agent is calcium oxide or calcium hydroxide.

9. An application of a high temperature resistant resin coated aramid paper according to any one of claims 1 to 5, characterized in that: The high temperature resistant resin coated aramid paper is used as heat conductive insulating paper in electrical insulation equipment of large motors, reactors and transformers.

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